Objective：To evaluate the application value of early subclinical myocardial damage in patients with long COVID using two-dimensional speckle tracking imaging（2D-STI）technology. Methods：Fifty-nine patients with post-COVID infection after the unsealing of the COVID epidemic in China on December 7，2022 were enrolled as the observation group，and 60 pre-epidemic healthy people who were screened in the out patient department were selected as the healthy control group. Basic clinical data，markers of myocardial injury and other laboratory indicators of patients were collected. Two-dimensional echocardiography and 2D-STI were used to evaluate left ventricular ejection fraction（LVEF），left ventricular diastolic function（E/A，E/e’），global longitudinal strain（GLS）， and segmental strain values，and the heart rate，LVEF，E/A，E/e’，GLS，and segmental strain values were calculated and compared between the groups. Results：The study found that the left ventricular diastolic function E/A（1.14±0.34 vs. 1.46±0.44，P<0.001），E/e’ （8.01±2.08 vs. 7.21±1.53，P<0.05），and GLS［（-20.57±2.15）% vs.（-21.90±1.73）%，P<0.001］of patients with long COVID syndrome were significantly decreased compared to healthy control individuals. Further segmental strain analysis revealed significant decreases in ten segments，including basal anteroseptal，mid anterior，mid anteroseptal，mid inferolateral，mid anterolateral，apical anterior，apical anteroseptal，apical inferior，apical inferolateral and apical anterolateral in the COVID group（P<0.05）. Subgroup analysis based on post-infection time found that as the recovery time from COVID prolonged，the GLS of patients showed a gradual improvement trend. Conclusion：Patients after COVID infection often experience a decrease in left ventricular diastolic function and GLS. With the prolongation of COVID recovery time，the above indicators show a gradual improvement trend. The application of 2D-STI technique can quantitatively evaluate early subclinical myocardial injury in patients with long novel coronavirus syndrome，which may provide evidence for clinical diagnosis and treatment of COVID patients.